This proposal is for the Postmenopausal Estrogen/Progestin Interventions (PEPI) Trial Coordinating Center. PEPI is a multicenter, randomized, placebo-controlled clinical trial that will be designed to determine, in a 5-year program, which estrogen/progestin preparation(s) have the most favorable effect on selected risk factors for coronary heart disease and osteoporosis. The effects of the treatments on hemostatic factors, endometrial function, incidence of gallbladder disease and relief of menopausal symptoms will also be evaluated. A multidisciplinary team from the Center for Prevention and Biometry at the Bowman Gray School of Medicine has been assembled to function as the PEPI Coordinating Center. It includes expertise in biostatistics, data management, computing, cardiovascular disease, lipidology, obstetrics, osteoporosis, epidemiology, and the design, implementation and evaluation of clinical trials. This team will collaborate with the PEPI investigators and the NHLBI Program staff in developing the study protocol and the Manual of Operations, in designing a data collection system, in developing and monitoring quality control and in analyzing and reporting trial results. The Center will also organize and monitor the Central Laboratories and Reading Centers. Clinic data will be collected using a distributed data entry system that includes interval edit checks. Training procedures and quality control methods are proposed. The Coordinating Center will provide detailed reports of the trial data to the Steering Committee and the Safety and Monitoring Committee. Excellent facilities and strong institutional support exist for the Coordinating Center's participation in the PEPI trial.